One of the major attributes of the fluidized bed is the high rate at which heat can be transferred from the bed of particles to an immersed object. Coefficients of heat transfer on the order of 400 to 740 W\/m2 \u00b7 K (70 to 130 Btu\/ft2 \u00b7 h \u00b7 \u00b0F) are possible. This heat flow rate is two to ten times higher than that provided by normal convection or radiation. In addition, the rate of heat transfer in the full bed is relatively independent of the emissivity of the object that is immersed and the temperature level.<\/p>\n
The figure illustrates the nature of heat transfer in a fluidized bed. Under curve 1, the bed is nonfluidized in a static state with low heat transfer rates that increase only slightly with velocity. After the minimum fluidization velocity (Vmf) is reached, the heat transfer coefficient, or HTC (h), increases rapidly over a comparatively narrow velocity range (curve 2). At a certain optimal velocity (Vopt), the HTC reaches a maximum (hmax) and then tends to diminish as the fluidized bed attains more gaslike properties (curve 3). The actual heat transfer rate experienced in the fluidized bed depends on the fluidizing gas velocity and its thermal conductivity, the size and density of the bed particles, their thermophysical properties, and on the geometry and structural design features of the furnace.<\/p>\n
For more information, click on the link below (subscription required). Then scroll to Figure 8.
\nR Schneider; R. Mesquita; W Sch\u00fctzenh\u00f6fer, Distortion in Tool Steels, ASM International, 2014
\nhttps:\/\/doi.org\/10.31399\/asm.hb.v04d.a0005958<\/p>\n","protected":false},"excerpt":{"rendered":"
One of the major attributes of the fluidized bed is the high rate at which heat can be transferred from the bed of particles to an immersed object. Coefficients of heat transfer on the order of 400 to 740 W\/m2 \u00b7 K (70 to 130 Btu\/ft2 \u00b7 h \u00b7 \u00b0F) are possible. This heat flow […]<\/p>\n","protected":false},"author":63081,"featured_media":13907,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[440,441],"tags":[],"class_list":["post-13906","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news","category-news-articles"],"yoast_head":"\n